hello = "hello"
world = 'world'

print(hello .. world)	-- concat	
print("length: " .. #hello) 	-- get the length of string
print(hello, world) 	-- use tab as delimiter

-- escape characters
-- \ddd ---> d means decimal number (no more than 3)
-- \xhh ---> h means hexadecimal number, x means uses hexadecimal (no more than 2)
-- \u{h..h} ---> hexadecimal with no numbers limit
print("\\123: " .. "\123")
print("\\x45: " .. "\x45")
print("\\u{3b1}: " .. "\u{3b1}")

-- use [[ ... ]] to represent long/multi-line string 
page = [[
	<html> 		-- the indent will slso be printed
	<head> 		-- the comment will also be printed
		<title>An HTML Page</title>
	</head>
	<body>
		<a href="http://www.lua.org">Lua</a>
	</body>
	</html>
]]
print("page: " .. page)

-- we can add a '=' in [[ and ]]
-- like [=[ ... ]=] so that it will match it correctly
-- and [===[ ... ]===] is also ok, the number of '=' should be equal in a pair
long_str = [=[
	[[ this is
		 a multi-line
		 comment ]]
]=]
print("long_str: " .. long_str)
